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ZZR250 [93'] - Engine won't fire

Discussion in 'Technical and Troubleshooting Torque' started by Smokae, Nov 14, 2009.

  1. I have a 1993 ZZR250. I read the other thread below mine with a similar situation - a heavy shock to the bike leading to problems starting - rectified with a check of the battery terminals and solenoid.

    After I crashed the bike, it needed a full open throttle to get it moving again. I had no choice but to GTFO because it was at the lights. Riding off, it had next to no power, stalled "softly", i.e. not a gear type stall, but like, the RPM's just slowly and softly dropped and the engine simply cut out. It got more difficult and had less power the further I rode it :(

    Probably the wrong thing to do!

    Some other background is that some kids tried to steal it a few minutes prior, I don't think they did anything to it, I couldn't find anything tampered with.

    I believe my problem is different. Symptoms:

    - Bike won't start
    - All electrics functioning correctly
    - Starter motor is fine, I think - the rapid electric sounds you hear when you press the starter button are clear and sound normal
    - Fuel flow was my first guess, but putting the petcock into prime, fuel flows fine, it will come out the drain run off tube if i leave it > 5 seconds
    - Allowing 5 seconds of prime results in those first few "coughs" you get before the engine would normally start, but nothing beyond that

    What I'm yet to do - Hopefully this afternoon

    - Check battery charge and voltage
    - Drain the petrol tank so I can inspect the spark plugs - Unless someone can suggest another way to get at them!
    - Check the fuses

    I've stripped it down and checked it over, no loose wires. The engine was replaced 18,000kms ago. I really hope it has not seized :(
  2. You should be able to get to the plugs without draining the tank.. I've found that mine can be unbolted (with hoses still attached) and moved to the side of the bike, resting on the footpeg, and then ocky strapped so it cant fall off.
    I'm not suggesting you do exactly that, as they're different bikes.. but you should have SOME movement without taking the hoses off.
    Otherwise its not all that difficult to drain it anyway..

    You say you hope its not seized.. does this mean it doesn't turn over at all when you hit the starter? ie. just makes solenoid clicking noises, or is it turning over but not firing?

    If you can get to the spark plugs (and it does turn over nicely), that'd be a good place to start.. see what condition they're in.. sometimes can be covered in oil after dropping the bike and that causes misfiring and a few other issues.
    Also make sure each cylinder is sparking while you're there (rest the thread of the plug against the engine or frame to ground it before flicking the starter)

    Also how did you crash it? depending which way it fell can cause different things to happen

  3. #3 Smokae, Nov 14, 2009
    Last edited by a moderator: Jul 13, 2015
    The sound I am trying to describe is what you hear 6 seconds into this youtube video:


    i.e. immediately when I hit the starter button.

    I will check the plugs.

    The bike went tail over front and landed on it's right side. Had to replace the bracket for the rear brake, that was it...I had hoped :(
  4. That sound is normal turning over of the engine, not seized.

    Have you checked the kill switch?
    The tend to trip themselves in the event of a crash and in older bikes the contacts may be slightly corroded and wont complete the circuit when turned back on. Even if that hasn't happened, its a good idea to clean the contacts in the switch just in case.

    To be honest this sounds a lot more like fuel than anything else

    It may be flowing from the tank to the tap, but not from the tap to the carbs.. Try opening the drain at the bottom of the float bowl on the carby (you MAY need to remove the tank to get to the carbs, I'm not sure) but the drain is usually just a flat blade screw that seals shut a little spout underneath them.
    Once the float is empty, turn the tap to 'prime' and see if fuel flows out
    If you do need to get the tank off, just see if you can find a friend to hold it out of the way for you while its still connected

    If thats fine, and all the plugs are sparking ok then it could be something to do with blocked jets in the carbies or even blocked air intake

  5. This is just on/off kill switch on the handlebar right? I checked this, switched it back and forth, operates as normal, it seems.

    Would that be the contacts inside the switch casing?

    Ok, I realise I didn't exactly follow your instructions but this is what I did:

    - Drained the left float bowl, not seeing the other screw for the other bowl, attempted to start the engine. It sounded "closer" to starting, but no luck.
    - Realised there was another bowl to drain, so I drained both. Fuel came out of both the drain and non-drained bowl so it seems fuel is flowing
    - Attempted to start the bike: Had the starting noises then a very loud backfire...:-s ...and ran off.

    Should I go back and again drain the bowls, stick it in prime and let fuel flow out? It seems fuel is indeed flowing through to the carbie and into the bowls.

    If I dismantle the carbuerettor, will I have to replace the gaskets and gasket material?

    Unfortunately I can't inspect the spark plugs because they are DEEP inside the engine and my socket won't reach.
  6. Yeah thats the right switch, but sometimes it only cuts out the spark, and still lets the motor turn over. If the motor DOESN'T turn over when its switched to off, then its still working fine.
    Otherwise you still need to check for spark

    If you can't get the plugs out, try just unplugging one, and plugging in a spare one to test with. The result should be same.
    It would be good to see one of the plugs from the bike though, as you can find out if its covered in fuel or if its burnt etc

    If you empty the float bowls, and then fuel flows through when the switch is on 'prime', its not a fuel feed issue.
    But always close the drain valves before trying to start the engine.

    If you are careful in dismantling the carbs and dont damage any gaskets, they should be reusable. I'd recommend extra gasket goo stuff when putting it back together though, just to make sure its sealed (do not use silicon.. a previous owner did that to mine and it just melted in the fuel and went everywhere).
    And be careful to make note of which jets go where, as mixing them up will just cause more problems
  7. Standard sockets are usually way to short to accommodate a spark plug. However a plug socket or tube spanner shouldn't set you back too much. Invest in one and check your plugs.

    Having said that the chances of all plugs failing together are remote so if you have no spark it's unlikely the problem is the plugs. But at least it will help to eliminate/confirm one more thing.
  8. Well I finally managed to get the spark plugs out. Unfortunately I don't have a spare so I can't do this test.

    One has the tip very black, smells more "burnt" than the other, came out covered in what was seemingly a mix of fuel, oil, and carbon. There is still some carbon stuck between the thread, the sparking area is very black.

    I understand this needs to be replaced.

    The other plug was also swimming in the same crap but the tip is more gray than black, so I looked this up on the internet and apparently this spark plug is a correct colour? But anyway, I might replace it too...

    I'm waiting for Repco to get new plugs for me, I'll have them tomorrow morning, along with an update to this post :)

    On the carbie issue:

    I read that the drop might have resulted in the "muck" that settled at the bottom of the carbie to unsettle and block the jets. I'm not too keen in disassembling the carbie. Apparently if I squirt some petrol from a spray bottle into the air intake this will start the engine IF the spark plugs are not the issue - is this the air filter in the air box? Though that might apply only to lawn mowers :(
  9. Actually that works rather well with bikes too, but you'll need to remove the air filter, so that you can spray directly into the intake without any restrictions
    (the filter will just soak it all up)

    Also if you can get a hold of one.. a can of start ya bastard (yep, is actually called that) or carby cleaner is excellent for spraying in, because its a fine mist rather than huge droplets, and you can keep a constant feed going in whilst the engine tries to start

    If spark is fine, and you can start the engine by spraying stuff in.. but it stops again when you stop spraying, its likely the carbs will need cleaning.

    Whilst it may seem complicated, cleaning carbs is actually rather simple.. just delicate and takes a fair while to do. Your service manual should say the correct procedure on removing them, but after that you just have to take everything out that can possibly come out for cleaning (and remember how to put it back together)

    Take some photos of the carbs as you're disassembling if you want.. that way you won't have to remember

  10. Ok well I'll pick up a can of Aerostart from Repco.

    New plugs didn't help, at least it didn't backfire, I get that shallow, soft "pop" you often hear just before ignition but only once and it doesn't result in the engine firing :(
  11. One more thing, since you're going to be cranking it over a fair amount.. you should have the battery plugged into a charger, or have a spare car battery hooked up etc.. just to stop it running flat
    Every time you drain a battery it shortens its lifespan significantly

    Let us know how ya go with the magic spray :)

  12. I tried the aerostart, no luck. I removed the air filter, the spongey piece, and behind it is the metal foil/screen. I sprayed into there for 1 second, with no luck. Tried a second time, no luck.

    So I disconnected the battery and hooked it to the charger. Suspected there was no spark given the lack of ignition. Odd, since it backfired before.

    Apparently, the charger starts at the "draw" the battery is taking and then drops to zero once the battery is done charging. So i did this, it started at 2, then dropped to zero after 2-3 hours. The battery was making bubbles, caps were removed.

    I'll be taking the battery down to the bike tomorrow and see if it works.

    Not looking good! :(

    EDIT: I tried it with the new battery. It does the "woo-woo-woof" kinda sound you get over the regular engine noise when its just warming up, but it still does not start. Though I consider that closer...

    I guess it must be a spark issue then? Even though I replaced the plugs?
  13. Did you ever check to see if they were sparking or just replace them? If not then grab one of your old ones (or pull one out again) and with 3 still in and plugged in normally, have the 4th (or spare) plugged in and just resting the thread against the engine or frame.. something metal

    Then when you crank it over you should see if its sparking or not

    Ideally it should be a bright blue spark, if its a dull orangey/yellow its weaker than it should be (but should still start)
    And if you have no spark.. its time to check all your electrical connections, as well as the coils and whatever else a zzr uses for ignition :p
    My memory has gone a bit hazey since that last beer.. but there's usually like 3-4 things between the battery and the spark plug

  14. I tested both plugs, each are sparking blue sparks, though I think the left plug had a bit of orange to it.

    So if its sparking fine...why on earth didn't the spray work!
  15. sounds like crud in your carbs, my bike did a similar thing, it even backfired which sent me scurrying back into the house to hide for an hour or so. just pull them out, its easy, theres no bolts just hoses and the throttle/choke cables. get some nulon spray carb cleaner, drain the bowls and use about half the can of spray just spraying into every nook and little hole you can find on them, close the bowls and spray some in there again, then let them sit for a bit. open bowls and spray again etc. i had to do this because the screws on my carbs are stuck, and if i try and get them off the screw driver just digs into them. but it worked first go.

    a tip, wear safety goggles or sunnies or something or at least close your eyes when you spray, cause the stuff shoots out at different places, i copped an eyefull of carb cleaner and had a bad time :(

    also, i found that removing the drain screws in the bowls completly and spraying into the empty holes got more into the bowls... i think thats all the tips i have for you lol.
  16. Where are you located? Maybe someone can come have a look for you.
  17. Sorry about my lack of update.

    I'm in Sydney, Sutherland Shire.

    I read a carbie tutorial for this bike was too iffy about it. Perhaps I will dive into carbies when I have another bike to ride in the meantime but I really wanted my bike going and was stumped, so I took it to a mechanic.

    They looked at all the stuff I tried and said "Definitely carbs". 2.5 hours later they found the carbie was missing an o-ring and a spring...fixed up the mess inside, replaced the spare parts and it was running again. $260.

    Oh well, I learned a lot.
  18. Carbies are an art. unless you're very artistic dont touch.. ;)
  19. I had the exact same problem a week ago. I also have a ZZR250

    Your problem is most likely in the carbies. I bet when you crashed it your needle and seat got stuck so the carbies have been letting in too much fuel which is flooding your cylinders.

    Here is what you need to do.
    1. Take off fuel tank and side fairings to get to carbies.
    2. Take off carbies by unscrewing the hose clamps from left and right sides of bike.
    3. Remove spark plugs and blow out cylinders with an air compressor, this will get rid of any excess fuel in there. If you dont have an air compressor, leave the spark plugs out for a while to air it out. It is also important that you check your oil level and oil. I had found that fuel was leaking down through my cylinder and had thinned out my oil. Would be very bad to run the engine in this state :D
    4. Depending on how confident you are I would unscrew the bottom plates on each carby and check that the floats are stopping the fuel flow when fully elevated. I have found that even simply tapping the carby with the handle of a screwdriver is enough to free up the blockage and stop the carbies from flooding. I took my carbies apart completely and gave them a good clean. This link will help you http://myural.com/keihin_32cvk_disassembly.htm
    5. Put everything back together again and see if it starts. Make sure that your battery is nicely charged.
  20. Aww nuts! I just got my bike back yesterday.

    $200 to fix the carbie, it was the exact issue you spoke of, also required a new o-ring and a spring.

    Another $406 to fit new friction plates I provided, do a service, checked throttle and clutch cables and fit a (provided) rear brake plate. happy chappy :)